Plastic ophthalmic lenses provide several advantages over inorganic glass lenses, including being lightweight and shatterproof. However, plastic lenses often suffer from low refractive indices. Materials with a low refractive index do not allow thin lenses with the necessary degree of correction to be made.
Ophthalmic lenses can also be made to be photochromic, meaning that they can change color in response to changing light conditions. Plastic photochromic lenses also often suffer from relatively low refractive indices. Therefore, there remains a need for new compositions for plastic photochromic lenses that have relatively high refractive indices.